Fiber mat for battery plate reinforcement

ABSTRACT

Embodiments of the invention provide batteries, electrodes, and methods of making the same. According to one embodiment, a battery may include a positive plate having a grid pasted with a lead oxide material, a negative plate having a grid pasted with a lead based material, a separator separating the positive plate and the negative plate, and an electrolyte. A nonwoven glass mat may be in contact with a surface of either or both the positive plate or the negative plate to reinforce the plate. The nonwoven glass mat may include a plurality of first coarse fibers having fiber diameters between about 6 μm and 11 μm and a plurality of second coarse fibers having fiber diameters between about 10 μm and 20 μm.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a division of pending U.S. patent application Ser.No. 13/562,468 filed Jul. 31, 2012.

BACKGROUND OF THE INVENTION

Electrodes or electrode plates commonly used in lead-acid batteriesoften include a metallic grid that is used to support lead and/or leadoxide pastes. During charge and discharge cycles, the volume of the leadand/or lead oxide paste typically expands and contracts. Repeated usageand, thus, repeated charge and discharge cycles may have negativeeffects on the electrode, such as shedding of the active materialparticles of the lead and/or lead oxide pastes. To reduce these negativeeffects, the electrode may be reinforced with paper to keep the lead orlead oxide paste intact. While paper generally provides sufficienttensile strength for the reinforcement application, a potential problemwith paper is its vulnerability to degradation in the harsh chemicalenvironment within the battery. Degradation often weakens the paperrendering it less effective or ineffective for its reinforcementpurpose.

BRIEF SUMMARY OF THE INVENTION

Embodiments of the invention provide nonwoven fiber mats that can beused to reinforce plates in lead-acid batteries, or other batteries.According to one aspect, a lead-acid battery is provided. The lead acidbattery includes a positive plate having a grid of lead alloy materialpasted with a lead oxide material and a negative plate having a grid oflead alloy material pasted with a lead based material. A separator isused to separate the positive plate and the negative plate and thebattery also includes an electrolyte. A nonwoven glass mat is in contactwith a surface of the positive plate and/or the negative plate toreinforce the plate. The nonwoven glass mat includes a plurality offirst coarse fibers having fiber diameters between about 6 μm and about11 μm and a plurality of second coarse fibers having fiber diametersbetween about 10 μm and about 20 μm.

The nonwoven glass mat may have a thickness of 0.009 inches or less anda tensile strength of at least 35 lbs/3 inch. In one embodiment, thenonwoven glass mat has a thickness of 0.008 inches or less and a tensilestrength of at least 40 lbs/3 inch.

According to another aspect, a plate or electrode for a lead-acidbattery is provided. The plate or electrode includes a grid of leadalloy material and a paste of an active material applied to the grid oflead alloy material. A nonwoven fiber mat is disposed on a surface of,or within, the paste of the active material. The nonwoven fiber matincludes a plurality of first coarse fibers having fiber diametersbetween about 6 μm and about 11 μm and a plurality of second coarsefibers having fiber diameters between about 10 μm and about 20 μm.

According to one embodiment, the fibers of the nonwoven fiber matinclude: glass fibers, polyolefin fibers, and/or polyester fibers. Thenonwoven fiber mat has a tensile strength in the machine direction of atleast 20 lbs/3 inch. The nonwoven fiber mat may also have a tensilestrength in the cross-machine direction of at least 10 lbs/3 inch. Thenonwoven fiber mat has a mat thickness of about 0.009 inches or less,and more commonly a thickness of between about 0.006 inches and 0.008inches. In one embodiment, the first and second coarse fibers have fiberlengths between about ⅓ inch and about 1½ inch. In another embodiment,the first and second coarse fibers have fiber lengths between about ½inch and about ¾ inch. In yet another embodiment, the first coarsefibers and/or the second coarse fibers include fibers having a fiberlength of at least ⅓ inch. In a further embodiment, the first coarsefibers and/or the second coarse fibers include fibers having a fiberlength of at least ½ inch.

The nonwoven fiber mat may include between about 25% and 75% of thefirst coarse fibers and between 25% and 75% of the second coarse fibers.In another embodiment, the nonwoven fiber mat includes about 50% of thefirst coarse fibers and about 50% of the second coarse fibers. Thenonwoven fiber mat may be disposed within the paste of the activematerial between about 0.001 inches and about 0.020 inches from thesurface of the paste or plate.

In one embodiment, an additional nonwoven fiber mat is disposed on anopposite surface of the paste of the active material so that the pasteof the active material and the electrode are disposed between twononwoven fiber mats. The two nonwoven fiber mats may be opposite sidesof a bag that encloses or envelopes the paste of the active material andthe electrode.

The nonwoven fiber mat may further include a binder that is applied tothe mat between about 10% and 45% by weight of the mat. In anotherembodiment, the binder may be applied to the mat between about 20% and30% by weight of the mat.

According to another aspect, a method of manufacturing a plate of alead-acid battery is provided. The method includes providing a grid oflead alloy material, applying a paste of an active material to the gridof lead alloy material to form a battery plate or electrode, andapplying a nonwoven fiber mat to a surface of the paste of the activematerial. The nonwoven glass mat includes a plurality of first coarsefibers having fiber diameters between about 6 μm and about 11 μm and aplurality of second coarse fibers having fiber diameters between about10 μm and about 20 μm.

According to one embodiment, the nonwoven fiber mat is applied to abottom surface of the grid of lead alloy material prior to applicationof the paste of the active material and the method further includesapplying a second nonwoven fiber mat to a top surface of the paste ofthe active material so that the grid of lead alloy material is disposedbetween two nonwoven fiber mats.

The method may also include providing an additional grid of lead alloymaterial, applying a paste of an additional active material to theadditional grid of lead alloy material to form an additional batteryplate or electrode (the additional active material being either a leadbased material or a lead oxide material), positioning a separator matbetween the battery plate and the additional battery plate to form abattery cell assembly, positioning the battery cell assembly within acasing, and saturating the battery cell assembly with an electrolyte.

The nonwoven fiber mat may have a thickness of 0.009 inches or less anda tensile strength of at least 30 lbs/3 inch. According to anotherembodiment, the nonwoven glass mat may have a thickness of 0.008 inchesor less and a tensile strength of at least 40 lbs/3 inch.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is described in conjunction with the appendedfigures:

FIG. 1 illustrates an exploded perspective view of a battery cellassembly.

FIG. 2 illustrates an assembled cross section view of the battery cellassembly of FIG. 1.

FIGS. 3A-3C illustrate cross section views of various configurations ofan electrode or plate and a nonwoven fiber mat.

FIG. 4 illustrates a process for preparing an electrode or plate havinga nonwoven fiber mat disposed on or near a surface of the electrode orplate.

FIG. 5 illustrates a method of manufacturing an electrode or platehaving a nonwoven fiber mat disposed on or near a surface of theelectrode or plate.

FIG. 6 illustrates a method of manufacturing a battery cell assembly.

FIGS. 7A-10B illustrate various examples of nonwoven fiber mats havingfiber compositions similar to those described herein.

In the appended figures, similar components and/or features may have thesame numerical reference label. Further, various components of the sametype may be distinguished by following the reference label by a letterthat distinguishes among the similar components and/or features. If onlythe first numerical reference label is used in the specification, thedescription is applicable to any one of the similar components and/orfeatures having the same first numerical reference label irrespective ofthe letter suffix.

DETAILED DESCRIPTION OF THE INVENTION

The ensuing description provides exemplary embodiments only, and is notintended to limit the scope, applicability or configuration of thedisclosure. Rather, the ensuing description of the exemplary embodimentswill provide those skilled in the art with an enabling description forimplementing one or more exemplary embodiments. It being understood thatvarious changes may be made in the function and arrangement of elementswithout departing from the spirit and scope of the invention as setforth in the appended claims.

Embodiments of the invention provide nonwoven fiber mats that can beused to reinforce plates in lead-acid batteries, or other batteries. Thenonwoven fiber mats may replace other plate reinforcement means, such aspaper, that are currently used in lead-acid or other batteries. Thenonwoven fiber mats provide several advantages over the current platereinforcement means. For example, the nonwoven fiber mats do notdissolve in the electrolyte (e.g., sulfuric acid); they providevibration resistance, reduce plate shedding, and/or strengthen orreinforce the plate; and they provide good dimensional stability, whichmay allow easier guiding or handling during battery plate manufacturingprocesses.

The nonwoven fiber mats described herein also provide excellent strengthproperties as well as decreased mat size or thickness when compared toconventional fiber mats. These strength properties reinforce the plateswhile the decreased mat thickness reduces the overall volume that themat occupies, thereby allowing an increased amount of electrolyte and/oractive material paste to be used within the lead-acid battery, whichincreases the electrochemical process and, thus, the overall usefulnessof the lead-acid battery. The thinner nonwoven mats also improveprocessing efficiency by increasing the mat footage on the processingrolls, thereby reducing the frequency of roll changing. The nonwovenfiber mats may be less than 10 mils thick (i.e., 0.010 inches), and morecommonly less than 9 mils thick (i.e., 0.009 inches). In one embodiment,the nonwoven fiber mats are about 6 mils and 8 mils or between about 6mils and 7 mils thick.

The nonwoven fiber mats may have a total tensile strength of at least 30lbs/3 inch and more commonly at least 35 lbs/3 inch. To achieve thistensile strength, the nonwoven fiber mat may have a tensile strength inthe machine direction of at least 22 lbs/3 inch and a tensile strengthin the cross-machine direction of at least 13 lbs/3 inch. Thedescription of “lbs/3 inch” generally refers to a method of testing themat strength where a 3 inch by 12 inch rectangular piece of the fibermat is subjected to a tensile stress until the mat fails, such as byripping or tearing. Mats having tensile strengths less than 22 lbs/3inch in the machine direction and less than 13 lbs/3 inch in thecross-machine direction may not have sufficient strength to withstandwinding and rewinding during processing and/or to reinforce plates of alead-acid or other battery.

The nonwoven fiber mats may include glass fibers, polyolefin fibers,polyester fibers, and the like. The description herein will mainlydescribe using glass fibers, although it should be realized that theseand other fibers may be used. Preferably, any other fiber that is usedshould be able to withstand the acidic environment inside lead-acid orother batteries. The nonwoven fiber mats described herein include ablend of two or more different sized coarse diameter fibers. Thedescription of coarse diameter fibers generally includes fibers rangingin diameter between about 6 μm and about 22 μm in one embodiment, andbetween about 8 μm and about 20 μm in another embodiment.

For example, in one embodiment, the nonwoven fiber mats include a blendof first glass fibers having fiber diameters in the range of between 6μm and 11 μm with second glass fibers having fiber diameters in therange of between 10 μm and 20 μm. In one embodiment, the nonwoven fibermats include at least 25% of each of the first and second glass fibers.The glass fibers typically have fiber lengths that range between about ⅓of an inch to about 1½ inches, although fiber lengths are more commonlyabout ⅓ inch to ¾ inch or 1 inch. The nonwoven fibers mats also includea binder that bonds the glass fibers together. The binder is typicallyapplied to the glass fibers so that the binder comprise between about10% and 45% by weight of the nonwoven fiber mat, between about 15% and35% by weight of the nonwoven fiber mat, and more commonly comprisesbetween about 20% and 30% by weight of the nonwoven fiber mat. Thebinder is generally a chemically-resistant binder (e.g., an acrylicbinder) that delivers the durability to survive in the acid environmentthroughout the life of the battery, the strength to survive the platepasting operation, and the permeability to enable paste penetration.

The blended fiber mats described herein and/or battery plates orelectrodes reinforced with such mats may provide several advantages overconventional fiber mats, battery plates, and/or electrodes. For example,the described blended fiber mats may reduce the amount of activematerial (e.g., lead) used for the battery plate/electrode and, thus,reduce the overall thickness of the battery plate/electrode. Thisreduced thickness may be especially common in positive plates. The useof the described blended fiber mats may reduce the need to use moreactive material, such as lead, to provide strength to the plate.Further, the exposed surface area of the active material (e.g., lead)may increase, which is beneficial for the electrochemical reactions.Additionally, use of the described blended fiber mats may increase thecranking current with the appropriate design of other battery parts.

Having described several embodiments of the invention, additionalaspects will be more apparent with reference to the figures describedbelow.

Electrode, Battery, and Mat Configurations

FIGS. 1 and 2, respectively, show a perspective exploded view of alead-acid battery cell 200 and a cross-section assembled view of thelead-acid battery cell 200. Each cell 200 may provide an electromotiveforce (emf) of about 2.1 volts and a lead-acid battery may include 3such cells 200 connected in series to provide an emf of about 6.3 voltsor may include 6 such cells 200 connected in series to provide an emf ofabout 12.6 volts, and the like. Cell 200 includes a positive plate orelectrode 202 and a negative plate or electrode 212 separated by batteryseparator 220. Positive electrode 202 includes a grid or conductor 206of lead alloy material. A positive active material 204, such as leaddioxide, is typically coated or pasted on grid 206. Grid 206 is alsoelectrically coupled with a positive terminal 208. Grid 206 providesstructural support for the positive active material 204 along withelectrical conductivity to terminal 208.

Likewise, negative electrode 212 includes a grid or conductor 216 oflead alloy material that is coated or pasted with a negative activematerial 214, such as lead. Grid 216 is electrically coupled with anegative terminal 218. Like grid 206, grid 216 structurally supports thenegative active material 214 along with providing electrical conductanceto terminal 218. Positive electrode 202 and negative electrode 212 areimmersed in an electrolyte (not shown) that may include sulfuric acidand water. Battery separator 220 is positioned between positiveelectrode 202 and negative electrode 212 to physically separate the twoelectrodes while enabling ionic transport, thus completing a circuit andallowing an electronic current to flow between positive terminal 208 andnegative terminal 218. Separator 220 typically includes a microporousmembrane that has negligible conductance and may be any type ofseparator known in the art (e.g., AGM, polyolefin mat, and the like).

Positioned near a surface of negative electrode 212 is a nonwoven fibermat 230 (also referred to herein as a nonwoven glass mat or a glassmat). Glass mat 230 is disposed partially or fully over the surface ofnegative electrode 212 so as to partially or fully cover the surface. Asshown in FIGS. 3A-3C, glass mat 230 may be disposed on both surfaces ofthe negative electrode 212, or may fully envelope or surround theelectrode. Likewise, although glass mat 230 is shown on the outersurface of the electrode 212, in some embodiments glass mat 230 may bepositioned on the inner surface of the electrode 212 (i.e., adjacentseparator 220). Glass mat 230 provides an additional supportingcomponent for the negative active material 214. The additional supportprovided by glass mat 230 may help reduce the negative effects ofshedding of the negative active material particles as the activematerial layer softens from repeated charge and discharge cycles,thereby reducing the degradation commonly experienced by repeated usageof lead-acid batteries.

Glass mat 230 is often impregnated or saturated with the negative activematerial 214 so that the glass mat 230 is partially or fully disposedwithin the active material 214 layer. Impregnation or saturation of theactive material within the glass mat means that the active materialpenetrates into the glass mat. For example, glass mat 230 may be fullyimpregnated with the negative active material 214 so that glass mat 230is fully buried within the negative active material 214 (i.e., fullyburied within the lead paste). Fully burying the glass mat 230 withinthe negative active material 214 means that the glass mat is entirelydisposed within the negative active material 214. In one embodiment,glass mat 230 may be disposed within the negative active material 214 upto about a depth X of about 20 mils (i.e., 0.020 inches) from an outersurface of the electrode 212. In other embodiments, the glass mat 230may rest atop the negative active material 214 so that the glass mat isimpregnated with very little active material. Often the glass mat 230will be impregnated with the negative active material 214 so that theouter surface of the glass mat forms or is substantially adjacent theouter surface of the electrode 212 (see glass mat 240). In other words,the active material may fully penetrate through the glass mat 230 sothat the outer surface of the electrode 212 is a blend or mesh of activematerial and glass mat fibers.

Similarly, positioned near a surface of positive electrode 202 is anonwoven fiber mat or glass mat 240. Glass mat 240 may be arrangedand/or coupled with positive electrode 202 similar to the arrangementand coupling of glass mat 230 with respect to negative electrode 212.For example, glass mat 240 may be disposed partially or fully over thesurface of positive electrode 202 so as to partially or fully cover thesurface, may be positioned on an inner surface of the electrode 202(i.e., adjacent separator 220) instead of the shown outer surfaceconfiguration, and/or may be impregnated or saturated with the positiveactive material 204 so that the glass mat 240 is partially or fullydisposed within the active material 204 layer. Like glass mat 230, glassmat 240 also provides additional support to help reduce the negativeeffects of shedding of the positive active material particles due torepeated charge and discharge cycles.

The thickness of the glass mat is typically a function of mat weight,binder content (LOI), and fiber diameter. The type of binder used andthe length of the fibers may be weaker factors in determining the glassmat thickness. Higher binder content, however, generally reduces theglass mat thickness, although excessive binder use may pose variousprocessing challenges during mat production and thereafter. A lower matweight may also reduce the mat thickness. The mat weight, however, mayalso be limited because the mat needs to provide enough tensile strengthduring winding and downstream processes.

Blending coarse glass fibers, and preferably fibers in the range of 6-11μm and 10-20 μm, or any of the other ranges specified herein, mayproduce a mat having sufficient mat thickness and strength. For example,completely replacing coarse fibers (e.g., fibers between 10-20 μm) withfiner fibers (e.g., fibers ranging between 6-11 μm) may significantlydrop the strength of the mat and/or pose processing problems downstream,such as mat breakage when applying a lead, or lead oxide, paste during aplate reinforcement process. Additionally, to enable dispersion in awhite water solution, some of the fibers may need to be chopped shorter,which may reduce the tensile and/or tear strength of the glass mat. Forexample, 11 μm fibers may need to be chopped to a length of ½ inchinstead of ¾ inch, although in other embodiments 11 μm ¾ inch fibers areused. The glass mat fiber combinations described herein provide an idealrange of thinness and strength. For example, in one embodiment, finerglass fibers (e.g., fiber diameters between 6-11 μm) are blended withmore coarse fibers (e.g., fiber diameters between 10-20 μm), whichdecreases mat thickness while maintaining sufficient mat strength. Theblended coarse fibers may have roughly the same or similar lengths,which may provide a mat having improved or increased tensile strength.For example, 11 μm ¾ inch fibers may be blended with 13 μm ¾ inchfibers, which may produce a mat having improved tensile strength whencompared to a mat having single diameter coarse fibers (e.g., 13 μm ¾inch fibers). Further, the weight of the blended mat may be kept roughlyconstant or decreased.

Glass mats 230 and 240 (referred to hereinafter as glass mat 230)include a blend of two or more different diameter coarse fibers. In oneembodiment, glass mat 230 includes a plurality of first coarse fibers,having fiber diameters ranging between about 6 μm and about 13 μm,between about 6 μm and about 11 μm, or between about 8 μm and about 13μm. The first coarse fibers are blended with a plurality of secondcoarse fibers, having fiber diameters ranging between about 10 μm andabout 20 μm or between about 13 μm and about 20 μm. In anotherembodiment, glass mat 230 includes a blend of first coarse fibers havingfiber diameters between 6-11 μm or 8-11 μm and second coarse fibershaving fiber diameters between 10-20 μm or 13-20 μm. The blend of thetwo or more different diameter coarse fibers results in a mat that issufficiently strong to structurally support the active material asdescribed above and to withstand the various plate manufacturingprocesses while also minimizing the thickness and overall size of themat. Since glass mat 230 is a chemically and electrically inactivecomponent and, thus, does not contribute to the battery'selectrochemical process, reduced glass mat size is important in order tominimize the battery's volume of non-electrochemically contributingcomponents.

In one embodiment, glass mat 230 includes a blend of between 10% and 90%of the first coarse fibers and between 10% and 90% of the second coarsefibers. In another embodiment, glass mat includes a blend of between 25%and 75% of the first coarse fibers and between 25% and 75% of the secondcoarse fibers. In yet another embodiment, the blend of first coarsefibers and second coarse fibers is approximately equal (i.e., 50% of thefirst and second coarse fibers).

The length of the coarse fibers also contributes to the overall strengthof glass mat 230 by physically entangling with adjacent fibers or fiberbundles and/or creating additional contact points where separate fibersare bonded via an applied binder. In one embodiment, the first andsecond coarse fibers have fiber lengths that range between about ⅓ inchand about 1½ inches, although an upper length limit of 1¼ inch is morecommon. This range of lengths provides sufficient mat strength whileallowing the fibers to be dispersed in a white water solution for matprocessing applications. In another embodiment, the first and secondcoarse fibers have fiber lengths that range between ½ and ¾ of an inch.The fibers lengths of the first coarse fibers may be different than thefibers lengths of the second coarse fibers. For example, in oneembodiment, the first fibers may have an average fiber length of about ⅓inch while the second coarse fibers have an average fiber length ofabout ¾ inch. In one embodiment, either or both the first or secondcoarse fibers have an average fiber length of at least ⅓ inch, while inanother embodiment, either or both the first or second coarse fibershave an average fiber length of at least ½ inch.

The type and amount of binder used to bond the first and second coarsefibers together also contributes to the overall strength and thicknessof glass mat 230. As described above, the binder is generally achemically-resistant binder (e.g., an acrylic binder) that delivers thedurability to survive in the acid environment throughout the life of thebattery, the strength to survive the plate pasting operation, and thepermeability to enable paste penetration. Increased binder usage mayreduce the thickness of glass mat 230 by creating more fiber bonds anddensifying glass mat 230. The increased fibers bonds may also strengthenglass mat 230. In one embodiment, the binder is applied to the first andsecond coarse fibers such that the binder comprises between about 10%and 45% by weight of the glass mat 230 or between about 15% and 35% byweight of the glass mat. In another embodiment, the binder is applied tothe first and second coarse fibers such that it comprises between about20% and 30% by weight of the glass mat 230.

The above described glass mat 230 configurations provide mats having atotal tensile strength of at least 30 lbs/3 inch and more commonly atleast 35 lbs/3 inch. Specifically, the glass mats 230 have a tensilestrength in the machine direction of at least 22 lbs/3 inch and atensile strength in the cross-machine direction of at least 13 lbs/3inch. The above described mats have been found to have sufficientstrength to support the active material and to withstand the variousstresses imposed during plate or electrode manufacturing and processing(e.g., pasting or applying the active material). Glass mats 230 that donot have the above described tensile strength attributes may not besufficiently strong to support the applied active material (e.g.,prevent shedding and the like) and/or may pose processing issues, suchas mat breakage when applying the active material (e.g., lead or leadoxide) paste on the glass mat during the plate reinforcement process.

Further, the above described glass mat 230 configuration provide matsthat have a thickness of 10 mils or less (i.e., 0.010 inches) and morecommonly 9 mils or less (0.009 inches). In one embodiment, the glassmats 230 have a thickness in the range of between about 6 and 8 mils(i.e., 0.006 and 0.008 inches), and preferably about 7 mils. These matsoccupy minimal space within the electrode and battery interior althoughfor additional electrochemically active materials (e.g., additionalelectrolyte and/or lead or lead oxide paste) to be used, therebyincreasing the life and efficiency of the battery. The above describedmats have the unique combination of both minimal size or thickness andstrength. The mats may also have a pore size that ranges between 50microns-5 mm.

Referring now to FIGS. 3A-3C, illustrated are various electrode-glassmat configurations. FIG. 3A illustrates a configuration where anelectrode 300 has a single glass mat 302 disposed on or near an outersurface. This configuration may be similar to that described above forFIG. 2. The glass mat 302 may partially or fully cover the outer surfaceof electrode 300. The configuration of FIG. 3B is similar to that ofFIG. 3A except that an additional glass mat 304 is disposed on or nearan opposite surface of electrode 300 so that electrode 300 is sandwichedbetween the two glass mats, 302 and 304. Like glass mat 302, mat 304 maypartially or fully cover the opposite surface of electrode 300. FIG. 3Cillustrates a configuration where a glass mat 306 fully envelopes orsurrounds electrode 300. Glass mat 306 functions similar to a bag inwhich electrode 300 is placed.

Processes and Methods

Referring now to FIG. 4, illustrated is a process 400 for manufacturingan electrode. The process may involve transporting a lead alloy grid 410on a conveyor toward an active material 430 applicator (e.g., lead orlead oxide paste applicator), which applies or pastes the activematerial 430 to the grid 410. A nonwoven mat roll 420 may be positionedbelow grid 410 so that a nonwoven mat including a blend of coarse fibersas described herein may be applied to a bottom surface of the grid 410.Similarly, a nonwoven mat roll 440 may be positioned above grid 410 sothat a nonwoven mat including a blend of coarse fibers (similar to ordifferent from mat 420) may be applied to a top surface of the grid 410.The resulting electrode or plate 450 may subsequently be cut to lengthvia a plate cutter (not shown). As described herein, the active material430 may be applied to the grid 410 and/or top and bottom mats, 440 and420, so that the active material impregnates or saturates the mats to adesired degree.

Referring now to FIG. 5, illustrated is a method 500 of manufacturing aplate or electrode of a lead-acid or other battery. At block 510, a gridof lead alloy material is provided. At block 520, a paste of an activematerial is applied to the grid of lead alloy material. The activematerial paste may be a lead material or a lead oxide material dependingon if the plate or electrode is to be a positive or negative plate. Atblock 530, a nonwoven fiber mat (e.g., a glass mat) as described hereinis applied a surface of the paste of the active material, which mayinclude impregnating or saturating the nonwoven fiber mat as describedherein. It should be noted that the illustrated steps of method 500 neednot occur in a sequential manner so that the application of the nonwovenfiber mat occurs before the application of the active material paste.For example, in one embodiment, a nonwoven fiber mat is applied to abottom surface of the lead alloy grid, the paste of active material isapplied to the grid of lead alloy material and/or to the nonwoven mat asin block 520, and then a second nonwoven fiber mat is applied to a topsurface of the paste of active material. As described herein, thenonwoven fiber mat includes a blend of a plurality of first coarsefibers and a plurality of second coarse fibers. The first coarse fibersmay have fiber diameters ranging between about 6 μm and about 13 μm, 6μm and 11 μm, 8 μm and 11 μm, and the like, and the second coarse fibersmay have fiber diameters ranging between about 10 μm and about 20 μm, 13μm and about 20 μm, and the like.

Referring now to FIG. 6, illustrated is a method 600 of manufacturing abattery cell assembly of a lead-acid or other battery. At block 610, afirst grid of lead alloy material is provided. At block 620, a leadbased active material paste is applied to the first grid of lead alloymaterial to form a negative plate or electrode. At block 630, a nonwovenfiber mat as described herein is applied a surface of the lead basedactive material paste, which may include impregnating or saturating thenonwoven fiber mat as described herein. As described in FIG. 5, theillustrated steps need not occur in a sequential manner such as when theapplication of the nonwoven fiber mat occurs before the application ofthe lead based active material paste. Further, in a specific embodiment,a nonwoven fiber mat is applied to a bottom surface of the first grid oflead alloy material, the lead based active material paste is applied tothe first grid of lead alloy material and/or to the nonwoven mat, andthen a second nonwoven fiber mat is applied to a top surface of the leadbased active material paste.

At block 640, a second grid of lead alloy material is provided. At block650, a lead oxide active material paste is applied to the second grid oflead alloy material to form a positive plate or electrode. At block 660,a nonwoven fiber mat as described herein is applied to a surface of thelead oxide active material paste, which may include the described matimpregnation or saturation. Alternatively, the application of thenonwoven fiber mat may occur before the application of the lead oxideactive material paste as described herein. Further, in a specificembodiment, a nonwoven fiber mat is applied to a bottom surface of thesecond grid of lead alloy material, the lead oxide active material pasteis applied to the second grid of lead alloy material and/or to thenonwoven mat, and then a second nonwoven fiber mat is applied to a topsurface of the lead oxide active material paste.

At block 670, a separator is positioned between the first and secondplates or electrodes to form a battery cell assembly. As describedherein, the battery cell assembly may provide an emf of about 2.1 volts.At block 680, the battery cell assembly is positioned within a batterycasing. Step 680 may be repeated so that multiple battery cellassemblies are positioned within a battery casing to provide a desiredbattery voltage (e.g., 6.3 volts, 12.6 volts, and the like). At block690, the battery cell assembly is saturated with an electrolyte.

As described herein, the nonwoven fiber mats include a blend of aplurality of first coarse fibers and a plurality of second coarsefibers. The first coarse fibers may have fiber diameters ranging betweenabout 6 μm and about 11 μm, 8 μm and about 11 μm, and the like, and thesecond coarse fibers may have fiber diameters ranging between about 10μm and about 20 μm, 13 μm and about 20 μm, and the like. The nonwovenfiber mats may have similar fiber compositions or differentcompositions. Further, it should be noted that the above described stepsof method 600 need not occur in a sequential order so that various stepsare performed simultaneously and/or in a differing order.

EXAMPLES

Several nonwoven fiber mats having the fiber compositions describedherein were manufactured and tested for tensile strength and thicknessand the results are described below.

Referring to FIGS. 7A and 7B, illustrated are test results for severalmats manufactured from two different glass fibers; specifically, ¾ inch13 μm diameter T glass fibers and ⅓ inch 8 μm diameter C glass fibers(“C-1”) bonded with an acrylic binder to make a 0.40 lb/sq mat. Theillustrated graphs show the following four fiber mat compositions: 1)100% of the T glass fibers; 2) 75% of the T glass fibers and 25% of theC-1 glass fibers; 3) 50% of the T and C-1 glass fibers; and 4) 100% ofthe C-1 glass fibers. FIG. 7A shows the relationship between matthickness vs. acrylic binder content—i.e., loss on ignition (LOI)—at thedifferent blending ratios. The mat thickness was reduced with highercontent of the 8 μm C-1 glass fibers. FIG. 7A also shows that the twoblended fiber mats had thicknesses of about 9 mils or less, withthickness decreasing as binder content increased.

FIG. 7B shows the relationship between the total tensile strength(machine direction tensile strength plus cross machine direction tensilestrength) vs. LOI at the different blending ratios. The total tensilestrength was reduced with higher content of the 8 μm C-1 glass fibers.As shown, the 50% T and C-1 glass fiber blending ratio with an LOIcontent of approximately 28% provides a mat with a good combination ofthickness (i.e., less 8 mils) and tensile strength (greater than 40lbs/3 inch). The increased percentage of finer C-1 fibers results in athinner mat since the finer C-1 fibers are better packed. It isanticipated that an increase in length of the finer C-1 fibers, such asfrom ⅓ inch to ¾ inch, may increase the tensile strength of theresulting mat above that shown due to an increase in fiberglass surfacearea available for coupling with the binder and/or an increase in fiberjunctions.

Referring to FIGS. 8A and 8B, illustrated are additional test resultsfor mats manufactured from ¾ inch 13 μm diameter T glass fibers and ½inch 10 μm diameter C glass fibers (“C-2”) bonded with an acrylic binderto make a 0.40 lb/sq mat. The illustrated graphs show the following fourfiber mat compositions: 1) 100% of the T glass fibers; 2) 75% of the Tglass fibers and 25% of the C-2 glass fibers; 3) 50% of the T and C-2glass fibers; and 4) 100% of the C-2 glass fibers. FIG. 8A shows therelationship between mat thickness vs. LOI at the different blendingratios while FIG. 8B shows the relationship between the total tensilestrength vs. LOI at the different blending ratios. Mat thickness andtensile strength trends similar to those described for the blendedfibers mats of FIGS. 7A and 7B are observed for the blended fiber matsshown in FIGS. 8A and 8B. For example, the 50% T and C-2 glass fiberblending ratio with an LOI content in the range of approximately 20% to28% provide mats with a good combination of thickness (i.e., about 8mils or less) and tensile strength (i.e. about 40 lbs/3 inch orgreater).

Referring to FIGS. 9A and 9B, illustrated are additional test resultsfor mats manufactured from the C-1 and C-2 glass fibers bonded with anacrylic binder to make a 0.40 lb/sq mat. The illustrated graphs show thefollowing three fiber mat compositions: 1) 100% of the C-1 glass fibers;2) 100% of the C-2 glass fibers; and 3) 50% of the C-1 and C-2 glassfibers. FIG. 9A shows the relationship between mat thickness vs. LOI,while FIG. 9B shows the relationship between the total tensile strengthvs. LOI at the different blending ratios. Blending of the C-1 and C-2glass fibers produces a mat with intermediate thickness and tensilestrength. As shown, the 50% C-1 and C-2 glass fiber blending ratio withan LOI content of approximately 21% provides a mat with minimalthickness (i.e., about 6 mils) while still providing acceptable tensilestrength (i.e. above 30 lbs/3 inch), especially compared with the mathaving 100% C-2 glass fibers.

Referring to FIGS. 10A and 10B, illustrated are additional test resultsfor mats manufactured from the ¾ inch 13 μm diameter T glass fibers and½ inch 11 μm diameter T glass fibers bonded with an acrylic binder tomake a 0.40 lb/sq mat. The illustrated graphs show the following threefiber mat compositions: 1) 100% of the 13 μm T glass fibers; 2) 100% ofthe 11 μm T glass fibers; and 3) 50% of the 13 μm and 11 μm T glassfibers. FIG. 10A shows the relationship between mat thickness vs. LOI,while FIG. 10B shows the relationship between the total tensile strengthvs. LOI at the different blending ratios. Blending of the 13 μm and 11μm glass fibers produces a mat with intermediate thickness and tensilestrength. As shown, the 50% 13 μm and 11 μm glass fiber blending ratiowith an LOI content of approximately 20% provides a mat with a goodcombination of thickness (i.e., less than 8 mils) and tensile strength(i.e. about 33 lbs/3 inch), especially compared with the mat having 100%11 μm glass fibers.

Having described several embodiments, it will be recognized by those ofskill in the art that various modifications, alternative constructions,and equivalents may be used without departing from the spirit of theinvention. Additionally, a number of well-known processes and elementshave not been described in order to avoid unnecessarily obscuring thepresent invention. Accordingly, the above description should not betaken as limiting the scope of the invention.

Where a range of values is provided, it is understood that eachintervening value, to the tenth of the unit of the lower limit unlessthe context clearly dictates otherwise, between the upper and lowerlimits of that range is also specifically disclosed. Each smaller rangebetween any stated value or intervening value in a stated range and anyother stated or intervening value in that stated range is encompassed.The upper and lower limits of these smaller ranges may independently beincluded or excluded in the range, and each range where either, neitheror both limits are included in the smaller ranges is also encompassedwithin the invention, subject to any specifically excluded limit in thestated range. Where the stated range includes one or both of the limits,ranges excluding either or both of those included limits are alsoincluded.

As used herein and in the appended claims, the singular forms “a”, “an”,and “the” include plural referents unless the context clearly dictatesotherwise. Thus, for example, reference to “a process” includes aplurality of such processes and reference to “the device” includesreference to one or more devices and equivalents thereof known to thoseskilled in the art, and so forth.

Also, the words “comprise,” “comprising,” “include,” “including,” and“includes” when used in this specification and in the following claimsare intended to specify the presence of stated features, integers,components, or steps, but they do not preclude the presence or additionof one or more other features, integers, components, steps, acts, orgroups.

What is claimed is:
 1. A method of manufacturing a plate of a lead-acid battery, the method comprising: providing a grid of lead alloy material; applying a paste of an active material to the grid of lead alloy material to form a battery plate or electrode; and applying a nonwoven fiber mat to a surface of the paste of the active material, the fibers of the nonwoven glass mat being composed entirely of a blend of coarse glass fibers having average fiber diameters of between 6 μm and 20 μm including: a plurality of first coarse glass fibers having fiber diameters between about 6 μm and about 11 μm; and a plurality of second coarse glass fibers having fiber diameters between about 13 μm and about 20 μm; wherein the nonwoven fiber mat comprises between about 25% and 75% of the first coarse glass fibers and between 25% and 75% of the second coarse glass fibers.
 2. The method of claim 1, wherein the nonwoven fiber mat is applied to a bottom surface of the grid of lead alloy material prior to application of the paste of the active material, and wherein the method further comprises: applying a second nonwoven fiber mat to a top surface of the paste of the active material so that the grid of lead alloy material is disposed between two nonwoven fiber mats.
 3. The method of claim 1, further comprising: providing an additional grid of lead alloy material; applying a paste of an additional active material to the additional grid of lead alloy material to form an additional battery plate or electrode, the additional active material being either a lead based material or a lead oxide material; positioning a separator mat between the battery plate and the additional battery plate to form a battery cell assembly; positioning the battery cell assembly within a casing; and saturating the battery cell assembly with an electrolyte.
 4. The method of claim 1, wherein the nonwoven fiber mat has a thickness of 0.009 inches or less and a tensile strength of at least 30 lbs/3 inch. 